SWT - Model CAS -Conventional Activated Sludge System

CAS ( Conventional Activated Sludge ). It is originally the more traditional activated sludge system; it includes an aeration volume ( oxidation reactor ), used for biological degradation (activated sludge), and a secondary clarifier ( sedimentation basin ), where the sludge is separated from the treated wastewater. Currently, in most of the small-medium sized plants, the biological purification unit is performed with the Ludzack-Ettinger scheme consisting of two consecutive processes: the denitrification phase in anoxic conditions(absence of free oxygen), followed by an oxidation and nitrification phase in aerobic conditions : this is the case of the SWT-CAS Denitro-Nitro Calculation / Verification / Simulation Procedure :